Memory cell array

Abstract

Disclosed is a memory cell array including word and first bit lines and second bit lines respectively connected to memory cells, wherein each memory cell includes a MOS transistor and switching element having first and second conductive layers and a gap in which a resistance value changes by applying a predetermined voltage, and data is written by specifying the first bit line to connect it to a ground, specifying the word line and supplying a write voltage to the second bit lines, and read by specifying the first bit line to connect it to the sense amplifier, specifying the word line and supplying a read voltage lower than the write voltage to the second bit lines, and the word line is specified when the word line voltage becomes a gate threshold value voltage or more and a sum of a drive voltage and the gate threshold value voltage or less.

1. A memory cell array in which a plurality of memory cells are arranged in an array, the memory cell array comprising:
 a plurality of word lines respectively connected to the plurality of memory cells; 
 a plurality of first bit lines respectively connected to the plurality of memory cells; and 
 a plurality of second bit lines connected to the plurality of memory cells, 
 wherein each of the memory cells includes:
 a metal-oxide semiconductor (MOS) transistor; and 
 a switching element which is formed inside a contact hole including a first electrode connected to a first diffusion layer of the MOS transistor, 
 
 wherein the switching element includes:
 a first conductive layer; 
 a second conductive layer provided above the first conductive layer; and 
 a gap having a size of nanometer order which is formed between the first conductive layer and the second conductive layer, and in which gap a phenomenon that a resistance value is changed by application of a predetermined voltage between the first conductive layer and the second conductive layer occurs, 
 
 wherein each of the word lines is connected to a gate electrode of the MOS transistor, 
 wherein each of the first bit lines is connected to a second electrode connected to a second diffusion layer of the MOS transistor, 
 wherein each of the second bit lines is connected to the second conductive layer, and 
 wherein data is written by specifying one or more of the first bit lines connected to one or more of the selected memory cells to connect the one or more first bit lines to a ground, specifying one or more of the word lines connected to the one or more memory cells, and supplying a write voltage to the one or plurality of second bit lines, 
 wherein data is read by specifying the one or more first bit lines connected to one or more selected memory cells to connect the one or more first bit lines to the sense amplifier, specifying the one or more word lines, and supplying a read voltage which is lower than the write voltage to the one or plurality of second bit lines, and 
 wherein when the data is written or read, the one or more word lines are specified by allowing the voltage of the one or more word lines to be a gate threshold value voltage of the MOS transistor or more and to be a sum of a drive voltage of a circuit for specifying the one or more first bit lines and the gate threshold value voltage or less. 
 
     
     
       2. The memory cell array according to  claim 1  further comprising:
 a limiting member to limit the voltage of the first bit lines to the drive voltage or less. 
 
     
     
       3. The memory cell array according to  claim 1 ,
 wherein at least two second bit lines among the second bit lines are connected to each other.